Directional drilling systems are primarily applicable to horizontal directional drilling, and more specifically to earth and rock formation boring. In lateral or horizontal directional drilling, it is often necessary to bore or drill through an earth-bound formation, such as rock, and with the bit still remaining directable. This industry, sometimes called "trenchless digging," installs utilities around immovable objects, such as roadways, rivers and/or lakes, etc.
The conventional boring technique traditionally operates from a boring device or machine that pushes and/or rotates a drill string consisting of a series of connected drill pipes with a directable drill bit to achieve an underground path or direction through which a conduit or utility device can be installed. A sonde immediately follows the drill bit as it is directed around, over or under obstructions. The sonde transmits electronic positioning signals to a worker vertically above the sonde by way of a hand-held complementary receiving device.
A drawback of pre-existing sondes for horizontal drilling systems is a simple bolted-on cover for a sonde housing that is not robust enough to withstand the rigors of the horizontal directional drilling environment, especially when drilling through hard formations such as rock, where substantial vibration is incurred.